A gas turbine engine conventionally includes high and low pressure turbine rotors and one or more interturbine vane arrays in a duct between the low and high pressure turbine rotors. Cooling air is conventionally supplied to cool the outer duct wall and then enters the core cavity of the respective hollow vanes to cool the same and then is discharged from holes defined in the trailing edge of the vanes. Cooling air is thermodynamically “expensive” to the gas turbine engine cycle efficiency, and therefore, optimizing the secondary air flow consumption while providing adequate air flow and pressure margin is desirable.
Accordingly, there is a need for improvement.